1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus.
2. Description of the Related Art
In a light receiving sensor in which a photodiode has been constituted by forming a PN junction portion on a semiconductor substrate, a spectral region on which light can be received is determined according to a depth distance from the surface of the semiconductor substrate to the PN junction portion. In Japanese Patent Application Laid-Open No. 2001-326378, the size of a region on which carriers generated in a semiconductor layer of a first conductivity type can be detected is changed by changing the magnitude of a voltage to be applied to a semiconductor layer of a first conductivity type and a semiconductor substrate, thereby controlling sensitivity for the wavelength of incident light. Thus, it is possible to select either visible light or infrared light and then receive the selected light.
However, in such a case, there is a problem that a mixture of colors occurs since color separation is difficult in a spectral characteristic determined according to the depth distance from the surface of the semiconductor. On the other hand, in the photodiode in which the PN junction portions are made multilayered and separated up and down to improve color separation performance, there is a problem that optical signals under low luminance circumstances cannot sufficiently be obtained since photocarriers generated in an intermediate layer formed for a separation layer are discarded.